How & Why Solar Eclipses Happen

What’s more, a total solar eclipse is a rare event, cosmically speaking. There are close to 200 confirmed moons orbiting six major planets in our solar system (Mercury and Venus lack moons). But in only one instance is there a moon that’s the right size, and at the right distance from its planet, to just barely cover the brilliant solar disk and reveal the Sun’s wispy corona. And that’s our Moon. (Looked at another way, total solar eclipses aren’t rare; they occur roughly once every year or two somewhere on Earth. But any given spot on our planet’s surface gets darkened by the Moon’s shadow on average only once about every 400 years, so in that sense totality is indeed rare.)


Cosmic Coincidence
The Sun’s diameter is about 400 times that of the Moon. The Sun is also (on average) about 400 times farther away. As a result, the two bodies appear almost exactly the same angular size in the sky — about ½°, roughly half the width of your pinky finger seen at arm’s length. This truly remarkable coincidence is what gives us total solar eclipses. If the Moon were slightly smaller or orbited a little farther away from Earth, it would never completely cover the solar disk. If the Moon were a little larger or orbited a bit closer to Earth, it would block much of the solar corona during totality, and eclipses wouldn’t be nearly as spectacular.
Of course the Moon doesn’t totally eclipse the Sun every month — if it did, seeing totality wouldn’t be as much of a thrill. And even when the lunar disk encroaches on the Sun, it doesn’t always completely cover the solar disk. In fact, at new Moon — the only lunar phase when a solar eclipse can occur — the Moon usually misses the Sun altogether. Given all the variables, it’s almost surprising that we see eclipses at all.

Nothing Lasts Forever
The cosmic coincidence that gives us total solar eclipses isn’t permanent. The Moon is ever so slowly moving away from our planet at rate of about 1.5 inches (3.8 centimeters) per year. As it recedes, its average apparent diameter shrinks. Eventually, the Moon will never be large enough to completely cover the Sun, and total eclipses will no longer be visible from Earth’s surface.
And when might this sad prospect come to pass? The calculation is not precise — there are many unknowns such as whether the lunar retreat will continue at a constant rate and whether the solar diameter will remain stable over a long period of time. Still, about a billion years from now, give or take a few hundred million years, the surface of Earth will experience its final total eclipse of the Sun. Annular eclipses will continue to occur, though the percentage of the solar surface hidden by the Moon will gradually decrease.
So, when you stand in the lunar shadow watching the Moon pass between Earth and the Sun, revel in the knowledge that you are witnessing one of the most unusual and spectacula…

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Healthiest Time to Eat a Banana According to Its Ripeness

Take a moment right now to picture the perfect banana. What does it look like and how does it taste? Maybe you thought of a soft and sweet banana with tiny brown spots. Or you might have imagined a heartier banana with a light green peel.
It’s obvious that the taste, texture, and color of bananas change as they ripen. For that reason, everyone seems to have their own idea of what the perfect banana really is. But did you know that the nutritional content of bananas also changes as they age?The best way to understand how the health of a banana can change is by investigating what really happens to them internally over time. So let’s take a look.

Green Bananas
These bananas are youthful, full of life and also full of starch. Referred to as “resistant” starch, this nutrient makes your digestive system work a little harder. It’s also the reason why green bananas seem to fill you up so quickly. I must warn you; however, the starch in green bananas can also make you feel gassy or bloated.
The starch content in green bananas contributes to their waxy texture. These bananas aren’t quite as soft as their elders, which actually makes them perfect for cooking; they can take some heat.

If you’re looking for a banana that’s lower on the glycemic index, go for a green one. Eventually, your body will break this starch down into glucose. This way, green bananas will raise blood sugar levels slowly. The trade-off here is taste. Green bananas can be bitter, as they contain less sugar in every bite.

Yellow Bananas
Say goodbye to starch and hello to sugar. This gradual switch results in a softer and sweeter banana. While the yellow variety is higher on the glycemic index, they are actually easier to digest. With less starch to break down, your digestive system will soak up the nutrients quicker.
Unfortunately, there is always micronutrient loss as bananas age. To make up for this, yellow bananas are more developed when it comes to antioxidants. Your immune system will definitely appreciate a yellow banana.

Spotted Bananas
These bananas are older, wiser and sweeter. Not only do brown spots show that a banana has aged, but they also indicate how much starch has been converted to sugar. Think of all those brown spots as little sugar freckles. Ultimately, the greater number of brown spots a banana has, the more sugar it contains. You can also view brown spots as tiny immune system boosters. Spotted bananas are so rich in antioxidants that they have been linked to cancer prevention.


Brown Bananas
Do you remember all that resistant starch? Well, it’s practically all sugar now. These bananas can appear shriveled and mushy, but don’t give up on them just yet. Just as the starch has broken down into sugar, chlorophyll has taken a new form as well. This breakdown of chlorophyll is the reason why antioxidant levels increase as bananas age. So a fully brown banana is an antioxidant powerhouse.…

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